In the "Get Hot New Stuff Dialog" there are two things I noticed: 1. After click of "Install" of an item (like kdevelop documentation files which can be quite large) there could be a cancel action. 2. When there is an error, there is a label on the bottom of the dialog which is too small if the error message is not only one line.
The cancel functionality is a duplicate of BUG 413516. And the error label is only an issue in the old QWidgets dialog.